Edmunds' Inside Line editor Karl Brauer put $4.16 of electricity in his Chevy Volt, then hit a long, climbing California road. At 25.8 miles, the battery was spent, an energy-mile per dollar equation similar to a full-size pickup.

Plug-in hybrid advocates would argue the energy wasn't spent; it was stored in the hill. Math advocates would note that Brauer was using his Christmas lights the same month, and that his electric charges were closer to 23 cents per kWh, still making the Volt more efficient that most other vehicles Edmunds' drives up the same hill.